In compressed air systems, such as for supplying air under pressure to air operated motors, it is frequently desirable to filter out foreign matter and to remove water particles from the air before the air is delivered to the motor. To accomplish this it is common practice to direct the air through a filter mounted in a container that also has provision for collecting the water and for automatically discharging the water when it reaches a predetermined level within the container.
Heretofore the automatic drain valves for such units have been quite bulky, costly to produce, and subject to certain other disadvantages. One disadvantage is that the float for actuating the drain valve could get water logged and fail to function. Another disadvantage is that the parts have been difficult to assemble. Another is that certain components have not been readily accessible for replacement or repair.